A photoelectric conversion device is required to efficiently collect incident light on the photo-sensing surface of a photoelectric conversion element. In a solid-state image sensing apparatus disclosed in Japanese Patent Laid-Open No. 06-224398, a resin gap layer is interposed between a microlens and the photo-sensing surface of a photoelectric conversion element, as shown in FIG. 1 in Japanese Patent Laid-Open No. 06-224398. A layer lower in refractive index than the gap layer is interposed between the gap layer and a transfer electrode for transferring the charges of the photoelectric conversion element. According to Japanese Patent Laid-Open No. 06-224398, obliquely incident light, which does not contribute to photoelectric conversion in a conventional technique, can enter the photo-sensing surface of the photoelectric conversion element by utilizing total reflection at the interface between the gap layer and the low-refractive-index layer.
However, the solid-state image sensing apparatus in Japanese Patent Laid-Open No. 06-224398 does not examine light entering a boundary region between the gap layer of a predetermined pixel and that of a pixel adjacent to the predetermined one. For example, when light, which travels perpendicularly to the photo-sensing surface of a photoelectric conversion element, enters the boundary region between the gap layer of a predetermined pixel and that of a pixel adjacent to the predetermined one, it is difficult to guide light to the photo-sensing surface of the photoelectric conversion element.
As the area of a pixel including a photoelectric conversion element decreases, the ratio of the area of the boundary region to the pixel area increases. Light entering the boundary region cannot be ignored.